So-called finned tube heat exchangers are widely used in a variety of applications in the fields of refrigeration, air conditioning and the like. Such heat exchangers are comprised of a plurality of spaced parallel tubes in which a first heat transfer fluid, such as water, oil, air or refrigerant, flows while a second heat transfer fluid, such as air, is directed across the outside of the tubes. To improve heat transfer between the first and second fluids, a plurality of fins comprising thin sheets of metal are placed on the tubes. Each fin has a plurality of openings through which the tubes pass generally at right angles to the fins and a large number of fins are arranged in generally parallel, closely spaced relationship along the tubes to form multiple paths for the second heat transfer fluid to flow across the fins and around the tubes.
The design of the fins is a critical factor in the heat transfer efficiency of the heat exchanger. Numerous fin designs have been proposed to enhance heat transfer efficiency, compactness and manufacturability of finned tube heat exchangers. Many of these designs have involved enhancements to the fins, such as interrupting the fins with a plurality of louvers or defining corrugations on the surface of the fins, to cause numerous disruptions of the hydrodynamic boundary layers which form with increasing thickness along the fins and decrease heat transfer efficiency.
Although it is known in the art that heat transfer efficiency can be increased in a finned tube heat exchanger by adding various fin enhancements such as louvers and corrugations to interrupt the flow of air between the fins, such prior art enhancements typically have the undesirable effect of increasing air side pressure drop as air flows through the heat exchanger. There is, therefore, a need for an improved heat exchanger fin which substantially enhances heat transfer efficiency without substantially increasing air side pressure drop.